Heretofore various platinum compounds and complexes thereof have been used as catalysts in the preparation of various organosilicon compounds. Examples of some of the platinum compounds and complexes which have been used as catalysts are chloroplatinic acid, platinum chloride-cyclopropane and platinum complexes which have been prepared by reacting alcohols, ethers and aldehydes with chloroplatinic acid as well as platinum supported catalysts.
Chloroplatinic acid is generally one of the more useful catalysts but it has certain disadvantages. For example, chloroplatinic acid is insoluble in many organic materials and it is not always effective at low concentrations. These disadvantages have led to the discovery of the aformentioned organic platinum complexes. While these complexes provide certain improvements over chloroplatinic acid, they have certain disadvantages. For example, complexes such as disclosed in U.S. Pat. No. 3,220,970 to Lamoreaux, require long reaction times at elevated temperatures. Moreover, if the temperature is allowed to go above the parameters described, then metallic platinum is often obtained due to decomposition. Generally, a number of addition reactions are best effected, irrespective of the catalyst, at temperatures well above the temperature parameters described for making the catalyst in U.S. Pat. No. 3,220,970 to Lamoreaux. Consequently, the character of the platinum complex changes considerably under these conditions. Although these platinum complexes are more soluble than chloroplatinic acid in organic solvents, they are not sufficiently soluble in organosilicon compounds, especially organosilicon polymer systems where silicon bonded hydrogen groups are added to unsaturated organic compounds.
Platinum complexes of unsaturated siloxanes are described in U.S. Pat. No. 3,715,334 to Karstedt, in which a platinum halide is reacted with an unsaturated silicon material and the resultant complex is then treated with a base to remove the available inorganic halogen.
Other platinum catalysts which promote hydrosilation of unsaturated organic compounds are described in U.S. Pat. No. 3,795,656 to Martin, in which ammonium platinum organosilicon complexes are prepared by reacting chloroplatinic acid with an aminofunctional silicon compound. Although these ammonium platinum organosilicon complexes are effective in promoting the hydrosilation of unsaturated compounds, they are too slow for certain applications, such as in preparing dental impressions. Merely increasing the concentration of the platinum catalyst has not, in some instances, increased the rate of hydrosilation. In fact, it has been found that when the concentration of the platinum catalyst, has been increased beyond a certain range, the rate of hydrosilation has not been accelerated and often times has even slowed the reaction down to such a rate that it is no longer effective as a catalyst for hydrosilation.
Furthermore, it is known that nitrogen containing compounds retard room temperature curing of a system which cures by platinum catalyzed hydrosilylation of unsaturated organic compounds. For example, U.S. Pat. No. 3,192,181 discloses that benzotriazole will completely prevent room temperature curing of a platinum catalyzed hydrosilylation system. Likewise, U.S. Pat. No. 3,723,567 discloses that amine-functional silanes will inhibit room temperature curing of a platinum catalyzed hydrosilylation system. Thus, it is surprising that an ammonium platinum silicon complex containing nitrogen can be activated to effect hydrosilation at room temperature.
Therefore, it is an object of this invention to provide a novel catalyst. Another object of this invention is to provide a catalyst for effecting the addition of organosilicon compounds to unsaturated organic compounds at room temperature. Still another object of this invention is to provide an ammonium platinum silicon complex as catalysts for effecting the addition of silicon bonded hydrogen compounds to aliphatic unsaturated organic compounds. A further object of this invention is to provide a catalyst system which is soluble in both organic solvents and organosilicon compounds. A still further object of this invention is to provide a catalyst which is more stable at elevated temperatures for longer periods of time.